Separate Self-Synchronizing Packet-Based Scrambler Having Replay Variation

1. A separated self-synchronizing packet-based scrambler, comprising: a first data scrambler for receiving an input data stream and filtering the input data stream into a filtered signal using a feedback filter and a key signal, the first data scrambler having a first initial condition and including a means for forming the key signal; and a second data scrambler coupled to said first data scrambler to receive the filtered signal from the first data scrambler and to convert the filtered signal into a scrambled signal using a scrambling seed, the second data scrambler, having a second initial condition, comprising a random series generator for generating the scrambling seed for converting the filtered signal to a scrambled signal.

2. A separated self-synchronizing packet-based scrambler as recited in claim 1 , wherein the random series generator is a pseudo noise code generator.

3. A separated self-synchronizing packet-based scrambler as recited in claim 2 , wherein the pseudo noise code generator uses a primitive polynomial to generate the scrambling seed.

4. A separated self-synchronizing packet-based scrambler as recited in claim 1 , wherein the coupling of the first and second data scramblers allow a receiver to automatically correct errors in a packet-based data communication system that includes error coding and wherein the second initial condition is varied in the second data scrambler to provide replay variation and the first initial condition of the first data scrambler is fixed.

5. A separated self-synchronizing packet-based scrambler as recited in claim 4 , wherein the error coding is generated by a Reed-Solomon coder circuit.

6. A separated self-synchronizing packet-based scrambler as recited in claim 4 , wherein the packet-based data communication system is a packet-based orthogonal frequency division modulation (OFDM) data communication system implemented in a wireless local area network (WLAN) in compliance with IEEE standard 802.11.

7. A separated self-synchronizing packet-based scrambler as recited in claim 4 , wherein the packet-based data communication system is a packet-based orthogonal frequency division modulation (OFDM) data communication system implemented in a wireless local area network (WLAN) in compliance with High Performance Local Area Network (HiperLAN) standards.

8. A separated self-synchronizing packet-based descrambler, comprising: a first data descrambler for receiving a transmitted scrambled input data stream from a transmitter and to convert the scrambled signal into a descrambled signal using a descrambling seed equivalent to the scrambling seed of the scrambler of the transmitter, the first data descrambler having a first initial condition, comprising a random series generator for generating the descrambling seed for converting the scrambled signal to a descrambled signal; and a second data descrambler coupled to said first data descrambler to receive the descrambled signal from the first data scrambler and to filter the input data stream into a filtered descrambled signal using a feedforward filter and a key signal, the second data descrambler having a second initial condition equivalent to the initial condition of the scrambler in the transmitter and the second data descrambler including a means for forming the key signal.

9. A separated self-synchronizing packet-based descrambler as recited in claim 8 , wherein the random series generator is a pseudo noise code generator.

10. A separated self-synchronizing packet-based descrambler as recited in claim 9 , wherein the pseudo noise code generator uses a primitive polynomial to generate the descrambling seed.

11. A separated self-synchronizing packet-based descrambler as recited in claim 8 , wherein the coupling of the first and second data descramblers allow a receiver to automatically correct errors in a packet-based data communication system that includes error coding and wherein the first initial condition of the first data descrambler is varied to provide replay variation and the second initial condition of the second data descrambler is fixed.

12. A separated self-synchronizing packet-based descrambler as recited in claim 11 , wherein the error coding is generated by a Reed-Solomon coder circuit.

13. A separated self-synchronizing packet-based descrambler as recited in claim 11 , wherein the packet-based data communication system is a packet-based orthogonal frequency division modulation (OFDM) data communication system implemented in a wireless local area network (WLAN) in compliance with IEEE standard 802.11.

14. A separated self-synchronizing packet-based scrambler as recited in claim 11 , wherein the packet-based data communication system is a packet-based orthogonal frequency division modulation (OFDM) data communication system implemented in a wireless local area network (WLAN) in compliance with High Performance Local Area Network (HiperLAN) standards.

15. A packet-based data communication system having a transmitting device and a receiving device, wherein the transmitting device includes: a first data scrambler for receiving an input data stream and filtering the input data stream into a first filtered signal using a key signal, the first data scrambler having a first initial condition and including a means for forming the key signal, and a second data scrambler coupled to said first data scrambler to receive the first filtered signal from the first data scrambler and to convert the first filtered signal into a scrambled signal using a scrambling seed, the second data scrambler, having a second initial condition, comprising a random series generator for generating the scrambling seed for converting the first filtered signal to a scrambled signal; and wherein the receiving device includes: a first data descrambler for receiving the transmitted scrambled input data stream from the transmitting device and to convert the scrambled signal into a descrambled signal using a descrambling seed equivalent to the scrambling seed of the scrambler of the transmitting device, the first data descrambler, having a third initial condition equivalent to the second initial condition, comprising a random series generator for generating the descrambling seed for converting the scrambled signal to a descrambled signal; and a second data descrambler coupled to said first data descrambler to receive the descrambled signal from the first data scrambler and to filter the input data stream into a filtered descrambled signal using a feedforward filter and a key signal, the second data descrambler having an fourth initial condition equivalent to the first initial condition of the first data scrambler in the transmitting device and the second data descrambler including a means for forming the key signal.

16. A separated self-synchronizing packet-based scrambler as recited in claim 15 , wherein the random series generator is a pseudo noise code generator.

17. A separated self-synchronizing packet-based scrambler as recited in claim 15 , wherein the pseudo noise code generator uses a primitive polynomial to generate the scrambling seed and the descrambling seed.

18. A separated self-synchronizing packet-based scrambler as recited in claim 17 , wherein the coupling of the first and second data scramblers allow a receiving device to automatically correct errors in a packet-based data communication system that includes error coding, wherein the second initial condition and the third initial condition are varied to provide replay variation and wherein the first initial condition and the fourth initial condition are fixed.

19. A separated self-synchronizing packet-based scrambler as recited in claim 18 , wherein the error coding is generated by a Reed-Solomon coder circuit.

20. A separated self-synchronizing packet-based scrambler as recited in claim 18 , wherein the packet-based data communication system is a packet-based orthogonal frequency division modulation (OFDM) data communication system implemented in a wireless local area network (WLAN) in compliance with IEEE standard 802.11.

21. A separated synchronizing scrambler as recited in claim 18 , wherein the packet-based data communication system is a packet-based orthogonal frequency division modulation (OFDM) data communication system implemented in a wireless local area network (WLAN) in compliance with High Performance Local Area Network (HiperLAN) standards.